Over the past several weeks and months, we've seen a startling number of disease outbreaks pop up around the globe. It's a trend that's not completely surprising — one that could characterize the coming decades as the Age of Epidemics. Here are some of the scariest new diseases you need to know about.

At this point, the U.S. Center for Disease Control is not recommending that anyone change their travel plans because of MERS.

MERS is different from the coronavirus that causes SARS. Coronaviruses are unusually large RNA viruses that primarily infect the upper respiratory and gastrointestinal tracts of mammals and birds. They feature a series of surface projections that make them look like a solar corona, hence the name. These viruses are typically spread in the air, but the World Health Organization (WHO) is considering the possibility that MERS may have been transmitted directly by animals. And in fact, UAE scientists are currently investigating the possibility of transmission between camels and humans.

It's really attributed to two things. One is the spread out of Pakistan through the intense transmission there because of the suspension of the vaccine in one area. And then combined with an increase in vulnerability of some highly unstable areas like Syria where it's been able to get another foothold.

By the end of last year, some 60% of all polio cases were the result of international spread, with increasing evidence that travelers were the primary contributors. One of the biggest concerns is Pakistan and its volatile area of North Waziristan (which borders Afghanistan), where polio vaccinations have been banned by the Taliban.

Polio mainly affects young children and is usually spread through contaminated water. It's a crippling and potentially deadly infectious disease that invades the brain and spinal cord, causing paralysis. More about polio at the CDC.

Measles On the Rise

In 2000, the U.S. considered measles to be eliminated because of vaccines, but the disease is currently making a big comeback because of a trend of parents not to vaccinating their children and frequent international travel. One to two percent of the population is at risk for developing measles, even in a vaccinated community.

"I've seen a lot of measles outbreaks in developing countries where vaccines aren't available. I've stood by children's bedsides and cared for them as they suffered. It is heartbreaking to see these children suffer from a disease that is preventable," said Nadia Qureshi, MD, pediatric infectious disease specialist at Loyola University Health System.

"We are seeing a rise in children in the U.S. with measles because international travel has become so common. People bring it back from endemic areas and because it's highly contagious. If your child is not vaccinated, they are at risk."

The Chikungunya Virus is Proliferating Rapidly in the Caribbean

The Chikungunya virus is galloping across the Caribbean and will almost certainly hit the United States. The mosquito-borne virus, which was documented in the region for the first time in December 2013, is now resident in Haiti. In the neighboring Dominican Republic, there have been anywhere from 150 to 200 cases confirmed since March. The virus is not currently found in the United States, but given climate change, the proximity of the U.S. to the Caribbean, and high rates of travel, it'll only be a matter of time.

Image: Viroscience Lab.

The disease, which can cause a fever and joint pain for months to years, is rarely fatal. Most people recover within a week. There is no vaccine and it's spread by Aedes aegypti mosquito, which also transmits dengue fever in the region.

A New Kind of Bird Flu Has Been Found in Antarctic Penguins

A new kind of influenza virus has been detected in Adelie penguins in Antarctica, though it doesn't appear to make them sick. The recently discovered virus is unlike other avian flu strains, thus warranting further study. The finding also shows that avian influenza viruses can get down to Antarctica and be maintained in penguin populations.

Bovine Leukemia Is Transmissible to Humans

The CDC is reporting that bovine leukemia (BLV) has been found in human breast tissue. This is a strong indication that BLV can be contracted by and spread among humans. This is particularly frightening when considering that BLV-infected cattle are found worldwide. In the United States alone, about 38% of beef herds, 84% of dairy herds, and 100% of large-scale dairy operation herds are infected.

Studies done back in the 1970s indicated that transmission to humans wasn't possible. But the advent of immunoblotting, which is 100 times more sensitive than previous techniques, revealed BLV DNA in human breast tissue. The new report concludes:

In view of the potential public health implications of BLV in humans, future research should address how humans acquire BLV infection, how frequently BLV infection occurs in different populations, and whether the virus is associated with human disease.

An unknown form of kidney disease is afflicting male agricultural works, particularly sugar cane cutters, along the Pacific coast. Though researchers have known about it for at least 20 years, they're struggling to explain it. NPR reports:

"We don't know. That's the unfortunate part, and we do desperately need to find some answers," says Reina Turcios-Ruiz, a medical epidemiologist with the U.S. Centers for Disease Control and Prevention's office in Guatemala City.

This form of kidney failure, known as insuficiencia renal cronica in Spanish (or chronic kidney disease of unknown origin in English), is now found from southern Mexico to Panama, Turcios-Ruiz says. But it occurs only along the Pacific coast.

The disease is killing relatively young men, sometimes while they're still in their early 20s. Researchers at Boston University have attributed about 20,000 deaths to this form of kidney failure over the past two decades in Central America.

As the disease progresses, agricultural laborers, who may earn a couple of thousand dollars a year, if they're lucky, end up in need of dialysis that costs tens of thousands of dollars annually.

MRSA and the Pending Antibiotic Apocalypse

Methicillin-resistant Staphylococcus aureus is a strain of bacteria that has evolved resistance to a wide range of antibiotics, making it deadly and extremely difficult to treat. Indeed, it's expected that within a few decades we'll enter into the "post-antibiotic era," a time when even the most routine infections could threaten our lives.